David Moffett, the former group chief executive of the Welsh Rugby Union, is threatening to take legal action against his erstwhile employers, claiming he was defamed in a statement issued last week to member clubs by the governing body.

Moffett, who returned to Wales from New Zealand last month and drew up a financial plan for Welsh rugby, took exception to a word used in the statement signed by the union's chairman, David Pickering. He has demanded an apology by 5pm on Monday. The WRU said it was considering the request and would make a decision on Monday.

Moffett has toured the country holding question and answer sessions and he drew up a financial plan for Welsh rugby, which he posted on his website and sent to all 320 member clubs.

The WRU responded, claiming that the document was inaccurate and using an adjective that Moffett felt was defamatory. He sent an email to Pickering last week asking for a response and an apology, but after he had not received a reply by Saturday morning, he sent another one.

It said that he had briefed lawyers to take action against Pickering and the co-signatories to the statement unless he received a public apology by 5pm on Monday 3 March. The WRU has been asked to comment.

The WRU and Regional Rugby Wales meet on Monday to discuss a new participation agreement. The current agreement lapses at the end of the season and the two sides have not been able to reconcile differences over a number of issues, including central contracts, competitions and the way commercial deals are negotiated.

RRW issued a public statement to the Welsh government on Friday night calling for a public inquiry into the running of the game in Wales, saying that the lack of trust between the WRU executive and the regional organisations lay at the heart of the dispute over the participation agreement and claiming that governance needed to be improved.